The effects of the appetite stimulant megestrol acetate 1) alone and in combination with 2) testosterone replacement, 3) resistance training, and 4) resistance training and testosterone replacement are to be examined in underweight (body mass index <25) elderly (60-85 years old) men. Appetite, food intake, strength, body weight, body composition, muscle size, resting metabolic rate, functional capacity, quality of life, and habitual physical activity will be examined before the interventions, and six weeks, and twelve weeks after the initiation of the interventions.